One installation of OpenOffice.org 3.2.1 on Windows 7 had a recurring problem of taking too long to open the Open, Save, or Save As dialogs. …
When OpenOffice.org 3.2.1 was originally installed on a Windows 7 computer, the OOo dialogs opened normally and quickly. At some point they became extremely slow to open, taking approximately 55 seconds. Once open, the dialogs then operated normally and at normal speed, so that (for example) the actual saving or opening of a file takes no longer than normal. What was delayed was the opening of the relevant dialog.
The solution is to open Tools – Options – OpenOffice.org – General – Open/Save Dialogs, and select "Use OpenOffice.org dialogs". Dialogs now open quickly as expected.
OpenOffice.org community forum thread